Home: one time range across the health block, and failures that follow it

The health screen was fixed at 24 hours everywhere except its lists, which
were fixed at nothing: `failuresQueryOptions` read the newest 100 rows and
`HealthActivity` filtered them client-side, so on a busy engine the failures
list covered whatever few minutes 100 rows happened to span while the chart
beside it spanned a day — and pinning an older minute showed an empty card.

One `RangePicker` now sits on the Health heading and governs the whole block:
the tiles, the flow table, both charts and both lists. Presets are 1h / 6h /
24h / 7d — the collector prunes at `OBS_RETENTION_DAYS` (30), so a week is
behind the last one. The longer windows ask for coarser buckets, since a week
of minute rollups is ten thousand points nobody can see.

Failures get the escape hatch the runs already had: a pinned minute is asked
for with `since`/`until` rather than filtered out of what is held, and the
list itself is bound to the selected range. `RUN_DEPTH`/`EVENT_DEPTH` become
one `LIST_DEPTH`, which now buys coverage of the window on screen instead of
a fixed newest-N — narrowing the range is what makes the same rows reach the
whole of it. The "Failures (24h)" tile counts errors over the selected window
from the rollups the table is drawn from, so tile, column and chart agree.

The node-panel and edge trend curves get no picker. They are a Redis ring of
the last 120 values per message with no window to ask for, so hovering one
reveals what it actually shows — how many readings, and the span they cover.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XC2jX6Hdj7pxGGKzBTrbqB

NOTEPAD.md

@@ -13,8 +13,6 @@ should reopen it.
 
 ### To be sorted
 
-- BUG: Logs currently only have small time window compared to e.g. graphs (in the home view); can we fix this, especially for the purpose of tracing back events?
-- FEAT: we should introduce a unified way to select time ranges in graph views with some convenience buttons like -1h -6h -24h . Make sure this also applies to the smaller "trend" charts like shown in the node panel or on edges; here we could show the time range selector upon hovering the graph (presets are fine)
 - INFRA: ensure that all the packages/ dependencies needed to run fluksio are available on arm to make this software runnable on e.g. raspbian
 - INFRA: merge the philosophy statement at the beginning of vision.md into the rest of the document. Dissolve the decision dates and fold the decisions into a clean structure
 - BUG/UI mobile friendly support is degraded: 1) toolbar in the "Flows" viewport extend mobile viewport width 2) position of nodes should never be static; always adjust such that there are as few as possible overlaps (of nodes and edge labels) and direction is left to right (desktop) or top to bottom (mobile) with a minimal (but clean) overall edge length 3) Dashboard view is not mobile friendly at all; as dashboard design is infeasible on mobile, render all widgets in a vertically stacked order. This allows to inspect each widget and make changes. Layout changes are not a feature on mobile 4) the home view is not responsive; all items shown there should re-order on mobile such that no scrollbars appear. Make sure the mobile support is anchored in the design such that future work does not break it
@@ -63,7 +61,9 @@ is what M4 still waits on, together with porting the flows.
 - CHORE/FLOW: `Pipeline.flush` releasing a held value runs its cascade without a run id, so those executions land in the minute rollups but in no run. Threading the scheduling run's id through the queue item would close it.
 - CHORE/API: the metrics collector is a bus subscriber, so a storm that overflows the bus queue undercounts. The events dropped are the same ones the websocket drops; exact accounting would need the collector to be fed from the engine rather than the bus.
 - CHORE/API: `/observability/summary` reports the work queue's `depth` as the Redis stream length, which is the journal size (capped at `STREAM_MAXLEN`) rather than a backlog. The health screen shows `pending` instead; the field name still invites the wrong reading.
-- FEAT/UI: the health screen's window is fixed at 24 hours and the charts fold minute buckets in Python. A range picker (and `date_bin()` behind it) is the next step if anyone wants a week.
+- PERF/API: the health block picks its window now, but `/observability/timeseries` and `/observability/flows` still read every `metric_minute` row in it and fold them in Python. `bucket_s` only coarsens what comes back, so the 7d preset pulls a week of rows on each 30 s poll. `date_bin()` is what makes the long windows cheap.
+- CHORE/API: `/observability/summary` still returns `failures_24h`, which nothing reads any more — the Home tile counts errors over the selected window from the rollups instead. Drop the field, or let the summary take a window.
+- CHORE/UI: the Home block's "Changes" list is the newest 15 audit rows whatever range is selected. Deliberate — an audit trail is worth reading past the window — but it sits under a control that governs everything else on the screen.
 - CHORE/FLOW: run records for a deleted flow stay until the retention window passes, so a flow that no longer exists keeps appearing in the history. Deliberate — it is a record of what ran — but `forget_flow` could offer to clear it.
 - CHORE/API: nothing can ask the collector to flush now, so anything needing the tables to be current has to wait out `FLUSH_INTERVAL_S` — which is what the soak harness does before clearing its own rows.
 - CHORE/API: `MetricsCollector._start_run`'s `existing is not None` branch is unreachable: a redelivery only arrives after the record it would update has been dropped.
@@ -203,6 +203,7 @@ Open on purpose. Each names what should bring it back.
 - CHORE/INFRA: `requires-python` is capped below 3.14 because the MCP SDK wants a newer starlette there than the pinned `sentry-sdk<2` allows. Lift the cap when sentry-sdk moves to 2.x.
 - CHORE/INFRA: `bun run --filter frontend build` fails on this workspace with `crypto.hash is not a function` — Vite 7 wants Node 20.12+ and the host has 18. The Docker image builds fine, so it only bites local bundling; `bunx tsc` still type-checks.
 - FEAT/UI: an endpoint's edge routes straight across the graph, so it can pass behind a node that sits between the lane and the node it wires to. Readable, but a routed edge would be tidier.
+- FEAT/UI: the node-panel and edge trend curves take no range, unlike the health block. They are drawn from a Redis ring of the last 120 values per message, which has no window to ask for — a hover caption names what the curve covers instead of a picker promising a span nothing can serve. Reopen if per-message history ever gains a time window.
 - FEAT/UI: an e-ink rendering profile for a dashboard — motion off, hover-only affordances resolved to something visible, high-contrast palette, thick strokes, and a repaint cadence low enough for a display that takes a second to settle. Reopen when a panel with such a display is actually hung.
 
 ## Blocked